Lost back brakes

@sonny is bang on regarding the bleed screws , the R3 front and rear circuits are a bastard to bleed at the best of times . I took a stab in the dark replacing my fronts in the chance that was how the air was getting into the system and it was ! Seems they don't leak but they do seem to suck air in . No problems since and front brake is 1 finger powerful . Be warned tho , all comparible ebay buys just won't cut it in the perfect fit stakes . The OEM items that I had to buy are stupidly expensive .
 
@sonny is bang on regarding the bleed screws , the R3 front and rear circuits are a bastard to bleed at the best of times . I took a stab in the dark replacing my fronts in the chance that was how the air was getting into the system and it was ! Seems they don't leak but they do seem to suck air in . No problems since and front brake is 1 finger powerful . Be warned tho , all comparible ebay buys just won't cut it in the perfect fit stakes . The OEM items that I had to buy are stupidly expensive .
I dont ever buy anything from Ebay. Too many bad experiences.
 
15’ R3T rear brake failure 38,000+ miles.opened bleed screw and pushed pedal several times no fluid.Cracked line at rear reservoir and pumped pedal no fluid.rear master cylinder bad?
 
You never should open the bleed screw then push the pedal several times. You will draw air into the system. Pump the pedal/lever several times, then open the bleeder with the brake pedal depressed then close the bleeder before you take any pressure off the brake pedal.

Same with any lines or bleeders attached to the master cylinder.

Here is a typical video to help.

 
I understand this my point is it seems like rear master cylinder is by-passing internally anyone else had this problem?
 
Fill the master cylinder (wear safety glasses).

Loosen the bleed screw a little; place finger over the bleed screw and depress the rear brake [HOLD] (let air escape). Put finger over the bleed screw and let off the rear brake. Give it a couple of seconds then repeat.

When it starts to force off your finger, then bleed the system.

If this doesn't work, you may be correct mc bypassing.

hth
 
Loosen everything before lifting the bike. Slow, easy torqueing things once the bike is on the stand.

IMG_0615.JPG IMG_0616.JPG Clean and re-lube
IMG_0637.JPG IMG_0638.JPG IMG_0641.JPG IMG_0640.JPG Disasemble, clean, reassemble.
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With new pads the bedding procedure makes a big difference. Pads will not work well for 2 to 300 miles. Many loooong easy stops at first. Then the heat treatment stops.

Service both front and back calipers. No scratching the pistons or their beds allowed taking the seals out. Brake fluid makes for a good cleaner. Make sure seals are inserted correctly. Use the lube in the kit. It helps slide the pistons back in and sitting the seals well.

Buy speed bleeders. One set per bike. Do not contaminate the pads or disc surfaces with greasy fingers or dirty rags and such. Brake fluid is a good cleaner and paint remover.

speedbleedimages.jpg


Cleanliness is braking happiness.

This is a fun easy job. Makes you feel important when you are all done and you brakes work better than ever. Its like cleaning guns.

Find a Clean well lighted bench. Clean rags. Good brake cleaning products and an old toothbrush and QTips. Any brake cleaner can will do. Compressed air and eye protection. Good background music and cold beer. If you run into a corner call Scott Warp99 or Barbagris or even me ;) That's what I did.

Discs will get hot, both front and back. Use them both. They will turn purple like pipes if they are getting tooo hot. R3 discs develop freeplay in the clock and counterclockwise direction and the wooble direction. Some is OK. Check your brakes integrity function and cleanliness often. The shop just looks to see if you need pads when you change the tires. If they are fancy they will bleed your brakes once a year. Check to see if your pistons are loose and clean, Naaaaah.

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EBC Candy. Cheap, beautiful and British. If you'r still not braking after all this, I have no idea what to do.
 
DOT 5 silicone based brake fluid is not supposed to be compatible with DOT 4 glycol based stuff. From what I've read, it shouldn't be used in ABS systems also, designed for DOT 3 or 4. Not sure if this would have caused an issue.

There is a DOT 5.1 which is glyol based that can be used though.
This week I replaced the fluid in the rear master with DOT 4. I have a good pedal now. I will check it on the next nice day. Having cruddy weather on Cape Cod the last few days.
 
Guys look at the rear brake bleeder. Mentioned it early in the post. You can go off into all the science and technical sh%t but simple says simple do. Stock bleeder is a joke and leaks air. Replace and have had no issues since. Back brakes have worked fine since then.
This week I replaced the brake fluid in the rear with DOT 4. While doing so, I took out the bleeder to inspect the seating of the bleeder. I did notice there is paint or powder coat on the seat of the bleeder screw. I gave the seat a quick sand with a piece of 1500 paper to get the coating off of it. I bled the brakes, have a great pedal now. So I put a mityvac on the bleeder and pulled a vacuum on the bleeder to see if I could get it to leak. No signs of anything. I will check the rear on the next nice day. So far so good.
 
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